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-rw-r--r--include/linux/pipe_fs_i.h39
1 files changed, 37 insertions, 2 deletions
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 8ff23bf5a819..3cc4f8eab853 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -31,6 +31,33 @@ struct pipe_buffer {
unsigned long private;
};
+/*
+ * Really only alpha needs 32-bit fields, but
+ * might as well do it for 64-bit architectures
+ * since that's what we've historically done,
+ * and it makes 'head_tail' always be a simple
+ * 'unsigned long'.
+ */
+#ifdef CONFIG_64BIT
+typedef unsigned int pipe_index_t;
+#else
+typedef unsigned short pipe_index_t;
+#endif
+
+/*
+ * We have to declare this outside 'struct pipe_inode_info',
+ * but then we can't use 'union pipe_index' for an anonymous
+ * union, so we end up having to duplicate this declaration
+ * below. Annoying.
+ */
+union pipe_index {
+ unsigned long head_tail;
+ struct {
+ pipe_index_t head;
+ pipe_index_t tail;
+ };
+};
+
/**
* struct pipe_inode_info - a linux kernel pipe
* @mutex: mutex protecting the whole thing
@@ -58,8 +85,16 @@ struct pipe_buffer {
struct pipe_inode_info {
struct mutex mutex;
wait_queue_head_t rd_wait, wr_wait;
- unsigned int head;
- unsigned int tail;
+
+ /* This has to match the 'union pipe_index' above */
+ union {
+ unsigned long head_tail;
+ struct {
+ pipe_index_t head;
+ pipe_index_t tail;
+ };
+ };
+
unsigned int max_usage;
unsigned int ring_size;
unsigned int nr_accounted;